Gas combustion apparatus include a gas fuel supply apparatus for supplying a gas fuel to a combustion chamber that burns the supplied gas fuel. Gas engines including a gas fuel supply apparatus are known as examples of the gas combustion apparatus, and one example of such a gas fuel supply apparatus is disclosed in Japanese Patent Application Laid-Open Publication No. 2008-106647 (hereinafter referred to as “the patent literature”).
According to the disclosure of the patent literature, the gas fuel supply apparatus includes mouthpiece attachment sections, to which mouthpieces of a plurality of gas containers (hereinafter also referred to as “cassette gas canisters”) are detachably attachable, are provided in parallel and in fluid communication with each other. Gas fuels contained in the plurality of cassette gas canisters are let out through the mouthpieces of the containers to the corresponding mouthpiece attachment sections, and then the gas fuels are supplied via the mouthpiece attachment sections to the gas engine. Using the plurality of cassette gas canisters, the gas fuel supply apparatus can secure an increased continued operating time of the gas engine.
However, during use of the gas engine, a temperature difference may occur between the cassette gas canisters due to different ambient temperatures of the gas canisters, and an inner pressure difference may occur between the cassette gas canisters due to such a temperature difference. Further, the mouthpiece attachment sections are provided in fluid communication with each other as noted above, and thus, when there has occurred an inner pressure difference between the cassette gas canisters, the gas fuel contained in one of the cassette gas canisters which has a higher inner pressure may undesirably flow into another of the cassette gas canisters which has a lower inner pressure. Therefore, with the gas fuel supply apparatus disclosed in the patent literature, it is difficult to continue supplying the gas fuels from the cassette gas canisters (gas containers) to the gas engine in a stable manner.